From owner-freebsd-net@FreeBSD.ORG  Thu May 24 21:05:59 2007
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Date: Thu, 24 May 2007 13:52:33 -0700
From: Luigi Rizzo <rizzo@icir.org>
To: Andre Oppermann <andre@freebsd.org>
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References: <20070524182545.GF89017@FreeBSD.org> <4655EEAD.2060307@freebsd.org>
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	from andre@freebsd.org on Thu, May 24, 2007 at 09:59:41PM +0200
Cc: net@freebsd.org
Subject: Re: TCP problems after 124 days of uptime?
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On Thu, May 24, 2007 at 09:59:41PM +0200, Andre Oppermann wrote:
> Gleb Smirnoff wrote:
> >   Yesterday two of our web servers running 6.2-PRERELEASE experienced
> > problems with accepting TCP connections. A small percentage of SYN
> > packets was ignored. The packets were seen in tcpdump output, but not
> > processed by TCP stack. No accept queue overflows occured, according
> > to 'netstat -sp tcp'.
> > 
> > Failing to find any clue I have rebooted one of them, and after
> > reboot is started to work flawlessly. Reboot also helped the second
> > one. Both servers were booted at the same time - 124 days ago.
> > 
> > Any ideas, any similar reports?
> 
> ticks is a 32 bit signed integer and TCP isn't really aware of it
> going negative and rolling over.  This is something I'm working on
> fixing in -current.  Haven't analyzed all potential cases there yet.

by chance, is your 'hz' set to 200 ?
this might explay something, because 2^31/(86400*200) = 124.275

	cheers
	luigi